Electrochemical Behavior of Hydride Ion in a LiF-NaF-KF Eutectic Melt

Abstract

The electrochemical behavior of hydride ion on a nickel electrode in a LiF-NaF-KF eutectic melt at 773 K has been studied by means of gas chromatography, cyclic voltammetry, chronopotentiometry and chronoamperometry. It was found that hydride ion is anodically oxidized at around 0.45 V vs. M⁺/M (M = alkali metal) and pure hydrogen gas is generated according to the following reaction:

H⁻ → l/2 H₂ + e⁻

This anodic process is a reversible, one-electron reaction governed by diffusion transport. The diffusion coefficient of hydride ion, , was estimated to be around 1 × 10⁻⁵ cm² s⁻¹ at 773 K.